Prospective two-year study of clinical outcomes following epithelium-off pulsed versus continuous accelerated corneal crosslinking for keratoconus

Importance Keratoconus is a debilitating condition with a disproportionately high impact on health resources and vision-specific quality of life. Background This study aimed to compare 2-year outcomes of epithelium-off pulsed (p-ACXL) and epithelium-off continuous (c-ACXL) accelerated corneal crosslinking in progressive keratoconus. Design Prospective, interventional case series. Participants Eighty eyes of 80 patients were included. Methods The visual, refractive and tomographic results of the two crosslinking protocols were compared. Main Outcome Measures Uncorrected distance visual acuity, corrected distance visual acuity (CDVA), manifest refraction spherical equivalent (MRSE) and maximum keratometry (K-MAX) on corneal tomography assessment. Results The mean patient age was 22.51 +/- 6.12 years (SD) and 22.08 +/- 5.72 years in the p-ACXL and c-ACXL groups, respectively. The mean CDVA significantly improved from 0.30 +/- 0.16 logMAR at baseline to 0.23 +/- 0.17 logMAR at 24 months (P = .04) in the p-ACXL group and from 0.36 +/- 0.22 logMAR to 0.26 +/- 0.27 logMAR (P = .02) in the c-ACXL group. The mean induced change in MRSE (+1.79 +/- 2.30 D vs +0.27 +/- 3.19 D, P = .04) and K-MAX (-1.75 +/- 1.80 D vs -0.39 +/- 1.95 D, P = .04) were superior in the c-ACXL group compared to the p-ACXL group at 24 months. No complications were encountered. Conclusions and Relevance In this prospective study, both p-ACXL and c-ACXL treatments were safe methods to halt the progression of keratoconus within a follow-up period of 24 months. c-ACXL appeared to offer superior refractive and tomographic outcomes when compared to p-ACXL but this did not translate into better visual outcomes.